The present invention relates to a multilayer structured laminate (hereinafter referred to as laminate) consisting of a core resin layer having projections and a skin.
The plastic laminates made of thermoplastic resins, etc., are used in large quantities for a variety of commercial products such as interior parts for automobiles, household electric appliances, etc., owing to their many advantages such as good economy, light weight and easiness of shaping.
There are also known the laminates in which a skin coat is applied on the surface of the core resin layer for alleviating the defects of the plastic laminates, such as cheap appearance, sense of coldness and vulnerability to scratches or disfigurements, while providing fashionableness and sense of softness to the products.
Such laminates can be produced, for instance, by supplying a skin material and a molten core resin into the cavity between the male and female molds, then clamping and cooling the molds. In such molding, a plurality of continuous or discontinuous projections may be provided on the side of the core resin layer opposite from the skin applied side for the purpose of reinforcing the molded product or facilitating attachment or joining of the molded product to other parts or elements.
However, production of a laminate by the above method has the problem that since cooling of the area around the intersection of the resin layer and each projection is delayed in the cooling step after clamping, sinks tend to be generated on the laminate surface at its positions corresponding to the projections on the back side due to volumetric shrinkage of the resin. This problem becomes even more serious as the width of the projection is enlarged or as the thickness of the core resin layer is reduced.